Pressure relieving closure



Dec. 5, 1961 J. w. WABER PRESSURE RELIEVING CLOSURE Filed Oct. 9, 1957 Anvemov 25 W W'abev v iv EM Jam M 4% Wilma; waig United States Patent 3,011,671 PRESSURE RELIEVING CLOSURE James W. Waber, Knoxville, Iowa (Pleasantville, Iowa) Filed Oct. 9, 1957, Ser. No. 689,145 4 Claims. (Cl. 215-40) This invention is a pressure relieving closure for receptacles containing gas. It consists of an elastic O-ring compressed between converging plane or curved surfaces to seal between them and stretched away from their convergence to unseal them. The O-ring is held in efiective position by its inherent elasticity. Pressures to which the O-ring is exposed and that are in excess of a predetermined value stretch the O-ring out along the converging surfaces until the O-ring loses contact with at least a portion of one of the converging surfaces. Gas will escape at this point and continue to escape until the pressure in the container is so reduced it is no longer sufiicient to stretch the O-ring. Its inherent elasticity will then pull it back into intimate contact with the converging surfaces to prevent further escape of gas and to retain important pressure in the container. The main characteristic of this invention, therefore, is the use of the inherent elasticity of an O-ring sealing element to act also in the capacity of pressure relief valve.

Thousands of peoplesuffer injuries, ranging from serious lacerations of face and hands to total destruction of eyesight, every year as a result of beverage container explositions. It is a' well known fact that many of these injuries could be prevented by using closures for these containers with relief valves built into them so that the contained pressure will never exceed a safe limit. It is thought that the main reason such closures are not now in general use is because the excessive cost of previously known pressure relieving closures made them commercially impractical. 'Ihe pressure'r'elief closure of this invention will provide a thoroughly reliable means for relieving excessive pressures in gas containers. Furthermore, as O-rings can be reused hundreds of times, expense to bottlers for example, will be less than with the usual crown cap that requires a gasket of some kind that is usually secured to and discarded with the cap. In at least the preferred form of the invention disclosed herein, standard equipment may be used to apply it to containers for carbonated beverages. The device may also be used with any other container in which gas pressures in excess of safe predetermined values are to be avoided.

Accordingly, it is the main purpose of this invention to provide a novel pressure relieving closure for containers: one that:

(1) Will relieve excessive pressures in containers and will reseal the containers to retain pressures of a predetermined value or less.

(2) Can be used with known containers and closure applying equipment.

(3) Can be provided at very low expense.

While the foregoing specifically listed objects are the principal ones for this invention, it is my intention to include as objects hereof any such as may be clear to a person skilled in the art after he" has examined this epecification and the accompanying drawings. The drawings are briefly described as follows:

FIG. 1 is an enlarged vertical section of a bottle neck and the preferred form of cap structure shown in sealed relation.

FIG. 2 is a still further enlarged vertical section of only one side of the structure shown in FIG. 1 illustrating the action of the O-ring in relieving pressure.

FIG. 3 is a vertical section similar to that of FIG. 1

ice

and drawn to the same scale as that figure showing a modification of the invention.

FIG. 4. is a vertical section of one side only of the structure shown in FIG. 3 but drawn to the same scale as FIG. 2; it shows the pressure relieving action of the modified form of the invention.

FIG. 5 is a vertical section of another modification of the invention drawn to the same scale as FIGURES 1 and 3.

FIG. 6 is a vertical section of a third modified form of the invention drawn to the same scale as FIG. 1.

In the drawings, 10 designates the illustrated portion of a well known form of crown capped bottle for beverages. It is the same in FIGURES 1 through 4. In the preferred form of the invention as shown in FIGURES 1 and 2, the crown cap 14 is modified from the usual form by having bulge 16 formed around its inside periphery. The bulge terminates in shoulder 18. The inside top of cap 14 is a smooth surface 19. As is clearly shown in FIGURES l and 2, surfaces 12 of bottle 10 and 19 of the cap converge toward the inside of the bottle neck. O-ring 20 closes the space between the two converging surfaces. when cap 14 is assembled to the-neck of bottle 10 as shown in FIG. 1. This is achieved by having the O-ring 20 a little smaller in diameter than it would be if 'it were capable of. resting on surface 12 as shown in FIG. 1 without being stretched. As cap 14 is affixed to bottle 10, therefore, O-ring 20 is forced down between the con verging surfaces 12 and 19 which places it under tension and compression. Cap 14 is secured to bottle 10 in the usual manner by bosses such as the one 22 crimped in under the head 24 of the bottle 10. When. the cap and bottle are secured together, surfaces 12 and 19 are held a fixed distance apart. In FIG. 1 it can be seen that there is a clearance 26 between cap 14 and O-ring 20 providing a space for outward stretching movement of the latter in response to gas pressure inside bottle 10 in excess of a predetermined safe pressure. When O-ring 20 is stretched by excessive internal pressures into space 26, the seal of the cap and bottle is broken as shown in FIG. 2. As soon as the escape of gas allows pressure to drop to the predetermined level, however, O-ring 20 overpowers the remaining pressure and contracts. Bottle 10 is sealed again as shown in FIG. 1 as soon as the O-ring contracts. O-ring 20 is held approximately centered in cap 14 before and during the process of capping bottle 10 by means of shoulder 18 that has an inside diameter less than the outside diameter of O-ring 20. O-ring 20 is made from any suitable elastic material.

In FIG. 3, the cap 30 is without the bulge and shoulder of the preferred form. It is secured to the bottle 10 in the usual manner, however, by crimping the cap edges in under the bead 24 as in FIG. 1. It is the manner of centering the O-ring 20 in the cap 30 that distinguishes this modified form of the invention from the preferred form. In FIG. 3, O-ring 20 is seen to be held to the cap in an approximately centered position by means of the adhesive 32. This manner of securing the ring to the cap produces a slightly diiferent action of the O-ring 20 when it relieves pressure in the bottle 10. The ring, instead of expanding straight out as in FIG. 2, is seen in FIG. 4 to swing out away from the sealing surface 12 with the adhesive 32 acting as a hinge. A solid line arrow in FIG. 4 shows the path of escaping gas.

FIG. 5 shows a modification of the structure shown in FIG. 3 in that the bottle numbered 34 has a sealing surface 36 in the form of a conical section. O-ring 20 is secured to a cap that is identical to the one of FIG- URES 3 and 4 and for that reason also numbered 30. Adhesive 32 in FIG. 5 is exactly like that in FIG. 3. Its releasing action is the same as that shown in FIG. 4,

It is elastic and is under a slight compression by the ridge. Cap 44 is similar to the ones of FIGURES 3 and 5 but has the long sides 46 to accommodate the extra distance from the top of the bottle to the base of the head 48. It is secured in the manner common for crown caps by .the bosses 50 crimped in' under the bead 48. v

While I have shown my invention applied to crown type capped bottle closures, it is apparent that the principle of converging surface sealed to each other by an elastic O-ring could be applied to other types of containers wherein pressures may increase as a result of a change in conditions afiecting the containers or their contents. These undesirable high pressures would be relieved while retaining pressures below the predetermined value.

I have disclosed my invention by both showing and describing practical embodiments of it. I now set out with the particularity required by statute the structure which I believe to be patentable.

I claim: 7

1. A pressure relieving closure for a container having a neck with a ridge near its top comprising, a cap having portions thereof crimped to engage the underside of the ridge on the neck of said container, said cap having an inner surface, the neck of said container having a surface thereon that converges toward the inner surface of said cap axially, an elastic O-ring under compression and tension between the converging surface of said container neck and the inner surface of said cap, and space within said cap surrounding said. O-ring and into which said O-ring radially may stretch far enough to disassociate it-.

self from at least a portion of the surfaces between which it is under tension and compression.

2. The pressure relieving closure of claim '1 in which a second ridge is formed on said neck above said axially converging surface on said neck of said container to re tain said O-ring on said container when said cap is removed.

3. A combination seal and pressure relief valve com- 1 prising an elastic O-ring under tension against inwardly converging surfaces with space radially around the outside of said elastic O-ring into which it can stretch in response to pressures on the converging side of said inwardly converging surfaces far enough to become disassociated, in part at least, from at least one of said converging surfaces. 7 V

4. A pressure relieving; closure for containerscornprising: a cap; an elastic O-ring in said cap; means for holding said elastic O-ring approximately centered in said cap; said cap constructed and arranged to leave' a space radially around said O-ring into which said O-ring can stretch when said cap is closing a container, and means on said cap for securing it to a container whereby said cap is limited in the distance it can move away from said container while said container is closed thereby and with said O-ringunder both tension and compression between axially converging surfaces comprising the inside of said cap and a surface on a containerwhen said cap is secured to the container.

References Cited in the file of this patent UNITED STATES PATENTS 

